Vacuum pump



FIG. 1 is a perspective view of a vacuum pump showing my new design;

FIG. 2 is a rear elevational view;

FIG. 3 is a top plan view;

FIG. 4 is a side elevational view;

FIG. 5 is a side elevational view showing the side opposite FIG. 4;

FIG. 6 is a front elevational view; and,

FIG. 7 is a bottom plan view.

The ornamental design for a vacuum pump, as shown and described.